Question

Diketahui sistem persamaan
5x+y=-2
2x+3y=-7
nilai xy=

Answer 1

Subsitusi jd hasilnya x= 1/13
y=-31/13
x.y = kalikan lah

Answer 2

5x+y=-2      x3        15x+3y=-6
2x+3y=-7    x1         2x+3y =-7   --
-----------------              --------------------
                               13x   = 1
                                   x = 1/13
5x+y = -2
5(1/13)+y = -2
5/13+y = -2
y = -2 - 5/13
y= -26-5/13
y= -31/13 

xy = 1/13*-31/13 = -31/169